The present invention relates to a sheet fixing device for fixing a light transmitting sheet to the framework of a vinyl house used as a greenhouse.
A sheet fixing device used in a vinyl house as a greenhouse usually comprises an elongated support frame having a narrow opening portion and an elastic retaining linear member fitted in the support frame, with a vinyl sheet being pressed and fixed into the support frame by using the retaining linear member.
On the other hand, sheet fixing devices capable of fixing a soft thin film about 0.1 mm thick satisfactorily in a greenhouse are disclosed, for example, in Japanese Utility Model Publication No. 54-42992 and Utility Model Registration No. 2094628.
The sheet fixing devices disclosed in the above publications each comprise an elongated support frame having a narrow opening portion, a dividable pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame. Centrally in the bottom of the pressing frame is formed a straight perforated line in the longitudinal direction or a notch which meanders in the longitudinal direction.
According to each of the above fixing devices, when a sheet is fitted into the elongated support frame through the pressing frame and the pressing frame is pressed to both sides with the urging member, the pressing frame holds the sheet grippingly in cooperation with the elongated support frame while being divided in two right and left through the perforated line or the notch, whereby wrinkling of the sheet can be prevented. Besides, since the pressing frame is present between the sheet and the urging member, that is, since the urging member does not contact the sheet directly, it is possible to prevent the sheet from being damaged by the urging member, or the rupture of the sheet caused by rubbing can be prevented.
However, in the sheet fixing device disclosed in Japanese Utility Model Publication No. 54-42992 in which a perforated line is formed in the pressing frame, the pressing frame becomes no longer employable once it is cut along the perforated line, and thus the said device is less economical. Moreover, when an attempt is made to push the sheet into the elongated support frame through the pressing frame, the tension of the sheet, in other words, a self-reverting force of the sheet acting to return to a horizontal state, is exerted on the back of the pressing frame, resulting in that the pressing frame may be bent inwards or warp in the opposite direction, with the perforated line as the center. Since the sheet fixing work is performed while suppressing such a motion, the working efficiency is inferior.
Further, for dividing the pressing frame along the perforated line, it is necessary to use an urging member having a strong resilience or a strong urging force, thus resulting in marked deterioration of the working efficiency, and the machining of the associated component becomes difficult. In view of this point, if the pressing frame is formed by molding a material which permits easy cutting along a perforated line, for example, a thin plastic material, the pressing frame will be overcome by the urging force of the urging member and be deformed partially or wholly, with wrinkling of the sheet. Besides, the pressing frame is apt to be deteriorated and is inferior in durability.
On the other hand, according to the sheet fixing device disclosed in Japanese Utility Model Registration No. 2094628 which uses a pressing frame with a meandering notch formed centrally, bending or warping of the pressing frame is somewhat remedied, but the operation for re-utilizing the pressing frame at the time of sheet replacement is extremely troublesome. More particularly, when the pressing frame is urged by the urging member at the time of fixing a sheet, it is divided in two right and left and is separated from each other. In the replacement of sheet, therefore, when the bisected pressing frame portions are taken out each independently from the inside of the elongated support frame and when an attempt is made to sandwich the sheet with the pressing frame portions after fitting a new sheet into the support frame, it is required to fit the right and left pressing frame portions one by one into the elongated support frame while making alignment of cut-in faces. At this time, the tension from the sheet is exerted on the back of each pressing frame portion and therefore it is necessary to perform the frame fitting operation while making the alignment against the said tension. Thus, the pressing frame mounting operation is very troublesome, causing deterioration of the working efficiency.
In the foregoing Japanese Utility Model Registration No. 2094628 there also is disclosed a technique such that the bottom of a pressing frame is expanded in an expander fashion through a plurality of notches. According to this technique, however, once the pressing frame is expanded laterally by an urging member, it can no longer revert to its original position by its self-reverting force and remains expanded. Therefore, when the pressing frame is used again at the time of sheet replacement, the work for taking out the pressing frame from the inside of the elongated support frame is troublesome, and also when fitting the pressing frame again into the support frame, its loading work is troublesome because of a too large width thereof.
It is an object of the present invention to provide a sheet fixing device for use in a vinyl house, capable of preventing wrinkling and breakage of a sheet, permitting the use of an urging member having a weak urging force, capable of being re-used repeatedly at the time of sheet replacement, and capable of remarkably improving the work for installing and removing a pressing frame.
For achieving the above-mentioned object, according to the present invention, in one aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a central support plate, guide slots formed longitudinally in both side positions of the support plate, and a pair of right and left retaining frames having horizontal bottom portions fitted transversely slidably into the guide slots respectively.
According to the present invention, in another aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a central support plate, a pair of right and left retaining frames disposed respectively on both sides of the support plate in a transversely slidable manner, and guide slots formed longitudinally in horizontal bottom portions of the retaining frames respectively, both side end portions of the support plate being fitted respectively into the guide slots.
According to the present invention, in a further aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a pair of right and left retaining frames disposed in a transversely slidable manner and a guide slot formed longitudinally in a horizontal bottom portion of one of the retaining frames, and a horizontal bottom portion of the other retaining frame is fitted in the said guide slot.
According to the present invention, in a still further aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a pair of right and left retaining frames disposed in a transversely slidable manner and guide slots formed longitudinally in horizontal bottom portions of the retaining frames respectively, the horizontal bottom portions of the retaining frames being fitted together slidably through the guide slots.
According to the present invention, in a still further aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a pair of right and left retaining frames formed at the same angle as the both side wall portions of the elongated support frame and in a transversely slidable manner, bottom frames integrally contiguous respectively to base ends of the retaining frames inclinedly upward or downward at a predetermined angle, and a guide slot formed longitudinally in at least one of the bottom frames, the other bottom frame being slidably fitted in the guide slot.
According to the present invention, in a still further aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising respectively from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a central support plate, guide slots formed longitudinally in both side positions of the support plate, a pair of right and left retaining frames formed on both sides of the support plate at the same angle as the both side wall portions of the elongated support frame and in a transversely slidable manner, and bottom frames integrally contiguous respectively to base ends of the retaining frames inclinedly upward or downward at a predetermined angle, the bottom frames being slidably fitted in the guide slots respectively.
According to the present invention, in a still further aspect thereof, there is provided a sheet fixing device comprising an elongated support frame having a narrow opening portion, the elongated support frame comprising a horizontal bottom portion and both side wall portions rising from both side ends of the bottom portion, a pressing frame fitted in the elongated support frame to hold a sheet grippingly in cooperation with the elongated support frame, and an urging member fitted in the pressing frame to urge the pressing frame against an inner wall of the elongated support frame, wherein the pressing frame comprises a central, horizontal support plate, a pair of right and left retaining frames formed on both sides of the horizontal support plate at the same angle as the both side wall portions of the elongated support frame and in a transversely slidable manner, bottom frames integrally contiguous respectively to base ends of the retaining frames inclinedly upward or downward at a predetermined angle, and guide slots formed longitudinally in the bottom frames respectively, both end portions of the horizontal support plate being fitted in the guide slots respectively.